African agricultural input subsidy programmes (ISPs) have primarily focused on conventional intensification: raising yields through increased use of inorganic fertiliser and improved seeds. Yet the yield effects from maize-focused ISPs have been smaller than anticipated, due in part to poor maize yield response to inorganic fertiliser resulting from low soil organic matter or pH. Joint use of inorganic fertiliser with complementary soil fertility management practices—for example, organic fertiliser or maize-legume intercropping—can contribute to more sustainable forms of agricultural intensification, while also improving yield response to inorganic fertiliser and the effectiveness of ISPs. We analyse the effects of Tanzania's ISP from 2008 to 2014, the National Agricultural Input Voucher Scheme (NAIVS), on use of these practices. Results from correlated random effects (CRE) multinomial logit (MNL) models suggest that NAIVS participation is associated with an 8–10 percentage point increase in the probabilities of inorganic fertiliser use alone and of joint use of inorganic fertiliser with organic fertiliser and/or maize-legume intercropping on consistent maize-growing households’ maize plots. CRE fractional MNL results suggest similar associations for the proportion of households’ total maize plots area under these practices. These results suggest that, in some cases, NAIVS may have contributed to sustainable intensification of maize production.

中文翻译：

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国家农业投入券计划（NAIVS）对坦桑尼亚玉米生产可持续集约化的影响

非洲农业投入补贴计划 (ISP) 主要侧重于常规集约化：通过增加使用无机肥料和改良种子来提高产量。然而，以玉米为重点的 ISP 对产量的影响比预期的要小，部分原因是由于土壤有机质或 pH 值低导致玉米对无机肥料的产量反应不佳。将无机肥料与互补的土壤肥力管理实践（例如有机肥料或玉米-豆类间作）联合使用，可以促进更可持续的农业集约化形式，同时还可以提高对无机肥料的产量响应和 ISP 的有效性。我们分析了坦桑尼亚 2008 年至 2014 年的 ISP，即国家农业投入凭证计划 (NAIVS) 对这些做法的使用的影响。相关随机效应 (CRE) 多项式对数 (MNL) 模型的结果表明，NAIVS 的参与与单独使用无机肥料和联合使用无机肥料与有机肥料和/或玉米的概率增加 8-10 个百分点有关- 在连续种植玉米的家庭的玉米地块上进行豆科作物间作。CRE 分数 MNL 结果表明，在这些做法下，家庭总玉米地块面积的比例具有相似的关联。这些结果表明，在某些情况下，NAIVS 可能有助于玉米生产的可持续集约化。